This invention relates to a release mechanism for safety ski bindings for amplifying the releasing force of a magnetic release system to a level sufficient to achieve release of a safety ski binding from a closed position to an open position, thus disengaging a ski boot from the ski.
For a skier's optimum safety and convenience, it is important that, while skiing, each ski boot is rigidly fixed with respect to the ski. On the other hand, in the event of an imminent fall it is important that the ski boot be disengaged from the ski to minimize possible injury to the skier. To achieve these goals, a wide variety of safety ski bindings have been developed for releasing a ski boot from a ski when the forces on the ski exceed a predetermined value.
Many ski bindings are entirely mechanical in nature. These mechanical bindings, while useful, tend to be somewhat unpredictable. Although the binding may be set to release when a predetermined force is applied, ice, snow, and dust may interfere with the binding's operation. Also, mechanical bindings often utilize mechanisms that latch the boot to the ski at the heel and toe of the boot. Such a binding detects only that component of applied force that acts on the heel or toe portion of the binding. This is adequate to achieve release when the skier falls either forward or backward, however, with twisting falls or with falls to the side, even though the total force may be sufficient to constitute a danger to the skier, the component of the force acting on the heel or toe of the binding may be insufficient to achieve release of the ski boot from the ski.
In recent years, electronic ski bindings have been proposed to overcome some of these disadvantages. Some of these bindings include sensors that detect not only the forces acting on the toe and heel portions of the ski boot, but additionally, the forces acting on the sides of the ski boot, such as occur with twisting falls or falls to the side. These sensors are designed to generate electrical signals when release is appropriate. Examples of such bindings are disclosed in U.S. Pat. No. 4,291,894 (D'Antonio, et al.), incorporated herein by reference.
While these improved ski bindings utilize an electronic system for detecting forces on the ski, the physical release of the ski boot generally involves a mechanical system. Thus, it is necessary to design electronic bindings so that the electrical signals will result in actuation of the mechanical ski boot release. To achieve this goal, an interface between the electronic and mechanical components of the ski binding is necessary. The interface must be activated by the electronic signals and, in turn, actuate the mechanical release system that controls physical release of the ski boot from the ski. Examples of such ski bindings are disclosed in U.S. Pat. No. 4,130,296 (D'Antonio, et al.), incorporated herein by reference. In that reference, a solenoid is utilized as an interface, while magnetic release systems for this use are proposed in earlier referenced U.S. Pat. No. 4,291,894.
An improved magnetic release system is disclosed in U.S. Pat. No. 4,484,761 (German Application No. P 31 28 185.0). This system utilizes a release arm with a small mass relative to the mass of a permanent magnet and an electromagnet. The arm is spring biased towards an actuating position and is held in a non-actuating position, against the spring force, by a magnetic field induced by the permanent magnet. When ski boot release is appropriate, an electrical impulse from the electronic component of the ski binding energizes the electromagnet, diminishing or cancelling the magnetic field induced by the permanent magnet. The release arm, no longer restrained in its non-actuating position by the magnetic field, moves under spring force to its actuating position in which the arm initiates ski boot release.
The above-described magnetic release system is advantageous for it is highly efficient with resulting low energy consumption; this, in part, because it is necessary only to diminish or cancel the magnetic field induced by a small permanent magnet, allowing spring force to move the release arm. Also, the system provides a reduced possibility of faulty release due to the small mass of the release arm relative to the mass of the permanent magnet and the electromagnet. A consequence of achieving these advantages is that the releasing force exerted by movement of the release arm from its nonactuating to its actuating position is relatively small; smaller, indeed, than the force necessary for releasing the ski binding from a closed to an open position. Thus, to achieve release of the ski binding and consequent release of a ski boot from the ski, it is necessary to enhance the force exerted by the release arm. This invention provides a convenient means of enhancing the releasing force of a magnetic release system.